In janitorial settings which require a significant amount and number of specialized cleaning solutions, the liquid cleaning products are purchased on a concentrated basis, and then are diluted to the proper strength at the site where they will be used. This type of general system is employed by a wide variety of users, e.g., hotels, hospitals, restaurants, etc. Several dispensing systems have been developed for mixing and diluting the concentrated cleaning product. The dispensers usually feature at least some of the following components: a container for the concentrated cleaning product, a storage container for the diluted cleaning product, a method to dose concentrate into the storage container, and a water supply line to dilute the concentrate.
The dispensing systems vary widely in terms of their complexity. The method of dilution may be rather simple and manual in nature, but may require a great deal of operator experience. On the other hand, the dispensing system may be quite complex, requiring several mechanical devices to dilute the concentrates. Such complex systems are often necessary where different cleaning products and different dilution ratios are utilized for different cleaning applications. These dispensing systems typically require several separate water lines, each water line corresponding to a different type of cleaning concentrate. The provision of multiple water lines increases the cost of installation, greatly limits the locations at which the dispensing system can be placed, and such a system is not portable. Accordingly, large containers such as mop buckets and auto scrubbers must be filled and taken to the point of usage by the janitorial personnel.
With one such system, a cabinet is mounted proximate the concentrated liquids and the water source. This cabinet contains a multiplicity of aspirators, backflow preventers and valves for dilution of the concentrates, the number of such devices depending upon the predetermined number established by the cabinet's manufacturer. However, such a system can be relatively complex, inflexible and expensive, especially in situations where only one concentrated liquid is utilized.
The cost of these conventional dispensing stations is relatively high, because of their complexity and because backflow preventers are generally required for each water connection by applicable plumbing codes. Pressure regulators may also be necessary to control use solution concentrations within an acceptable range. Other necessary flow control devices add to the cost of conventional dispensing systems. For example, a pickup probe and foot valve must be employed in order to withdraw the concentrate from a rigid container.
An aspirator is employed with some dispensing systems to withdraw the concentrated cleaning solution from its container. With conventional systems, each water line requires a separate aspirator, and the aspirators are located in a variety of places, such as mounted to the concentrate container or mounted upon the wall adjacent to the dispensing station. These locations of the aspirator add to the complexity and space requirements of the dispensing system. Other aspirators have been constructed that require changing the nozzle throat by removing the primary flow plumbing and forcing the nozzle component out and inserting a different nozzle and then reassembling the primary flow plumbing. Prior aspirators have also accommodated different flow requirements by offering various sized aspirator assemblies, which necessitated additional tooling, inventory and provided inflexibility after an installation had been made. Prior aspirators also used a fixed diameter nozzle to attain average results based on average conditions. Other aspirators do have a means to use different sized nozzles, but require the aspirator to be disassembled.
A number of prior systems use aspirators to form use solutions from concentrated chemicals. In one system, an aspirator that is permanently attached to a use solution reservoir is utilized. The spray gun is then attached to the aspirator to fill the use solution reservoir. In another system, an aspirator is employed that is permanently assembled to the spray gun. The assembly is then attached to the use solution reservoir or inserted into a bucket or other container to fill with use solution. With this system, the primary flow is fixed. In other systems, aspirators are used which are permanently fixed to a wall or equipment. To change the use solution concentration requires that concentrate pickup tubing be detached from the aspirator, the metering orifice be changed and the tubing replaced. No provision is made to modify the primary flow.
Another area in which liquid aspirators are commonly employed is the application of diluted solutions to lawns or garden foliage. These diluted solutions contain chemicals such as pesticides, fungicides, herbicides and fertilizers. Typically, sprayers of this type are attached to a garden hose, and the pressure of the water delivered to the hose is used to create a vacuum that causes a chemical solution in the sprayer to be aspirated into the water in order to provide a diluted solution that is subsequently sprayed. Sprayers of this type include a venturi chamber in which water from the garden hose is mixed with undiluted chemical solution from the sprayer's chemical solution container. In principle, as water passes through the venturi chamber, a syphoning or vacuum action is created by virtue of the velocity of the water passing through the chamber, to draw chemical from the container and into the venturi chamber for dilution with water from the garden hose. Many garden sprayers of this type have a fixed dilution ratio, although some sprayers allow for multiple dilution ratios but are typically of more complex construction, more expensive, and more difficult to use.
Besides their complexity, another drawback of many conventional dispensing systems is that the dilution of the concentrated chemical is inaccurate, resulting in a cleaning product having either too high or too low of a concentration. Many systems have no way of controlling and checking the dilution, so that inaccurate mixing by the janitorial personnel often occurs. Using too much concentrated liquid cleaner is wasteful, unnecessary, and expensive. Over-use of these products also hampers thorough rinsing and leaves messy residues. On the other hand, utilization of too little cleaning concentrate results in a use solution that will not clean adequately.
The present invention solves these and many other problems associated with currently available dispensing systems.